The invention relates generally to surgical instruments and particularly relates to computer controlled or assisted surgical instruments. Computer controlled or assisted surgical instrumentation typically involves the manual manipulation of instruments such as scalpels, scissors or catheters during surgical procedures with the aid of a computer. The computer may guide the movement of the instrument, may assist a surgeon in moving the instrument, or may simply monitor the movement of the instrument. The present invention is particularly useful in systems in which the movement a surgeon's hand is used to indirectly control the movement of the instrument via mechanical couplings and transmissions. As surgical instruments become more sophisticated, many of these devices will be monitored and possibly further controlled by computers.
Computer controlled surgical instrumentation has many advantages over conventional devices. For example, computer enhanced systems may coordinate many complex motions—more than is possible for the unaided human. These systems may scale motion arbitrarily, remove tremor, provide safe zones and limit forces. Computer systems may perform movement “macros” or stereotypical motion, such as suturing or knot typing. Even feedback processes, such as maintaining a constant grasp or probing for occlusions may be possible with advanced computer controlled surgical instruments.
Computer controlled instrumentation is particularly effective for minimally invasive surgical procedures, since access and visualization are severely limited. Minimally invasive techniques involve operating through small—typically 5 mm to 10 mm diameter—incisions, through which instruments are inserted. A video camera may also be inserted into the patient in order to view the operative site. Minimally invasive surgery is typically less traumatic than conventional surgery due, in part, to the significant reduction in incision size. Furthermore, hospitalization is reduced and recovery periods shorten as compared with convention techniques.
Although the surgeon has visual feedback from the surgical site, from either a camera, radiological imaging or ultrasonic scanning, the ability to control the relatively simple laparoscopic instruments remains difficult. Even with good visual feedback, the surgeon's tactile and positional sense are physically removed from the operative site rendering endoscopic procedures slow and clumsy.
Current instrumentation, with forceps, scissors, etc., inserted into the body at the end of long slender push rods is not fully satisfactory. The use of such conventional instrumentation increases operative time, and potentially heightens risk. For example, tissue may be injured when the laparoscopic tool moves outside the visual field. Moreover, there are limitations on the type and complexity of procedures that may be performed laparoscopically due, in part, to the limitations on the instruments that are used.
Development work has been undertaken to investigate the use of robots in surgery. Typically, these robotic systems use arms that reach over the surgical table and manipulate surgical instruments in a manner similar to the human operator. The presence of such a robot at the surgical site, however, may be problematic if the robot is too large or otherwise impedes access to the patient during surgery.
There is a need, therefore, for a surgical instrument that provides computer assistance yet does not impede access to the patient during surgery.
There is further a need for such a system that may be used for minimally invasive surgery.